Wall access panels.
The files are named after the size of hole they will cover. (They are 1" wider than the hole they cover)
Requires springs from cheap wooden mouse traps!
Use the pins from the mouse trap to attach the spring to the panel
For custom sizes here's the CAD link (OnShape)
Click → Make a Copy → Edit 1st sketch “Panel Dimensions” → Enter size of wall hole → Right click model, Export → STL
The author marked this model as their own original creation.